"Can push as well as gas" ... but for a much much much shorter length of
time ... here's one for you ... 1 hp, the amount of energy it takes to drag
a dead horse 100 yds :-)


"Lloyd Sumpter" wrote in message
...
On Sun, 30 Nov 2003 16:09:33 +0000, bowgus wrote:

Well that's the thing ... I did the calculation then, using formulae
scrounged
from sources I no longer remember, so ... the answer I got then was that
my
electric's 35 lbs thrust was about equivalent to a 1/4 hp outboard. But
I see
from "user" that a 36 lbs thrust electric is equal to about a 2.5 hp
(gasoline)
outboard ... which is A LOT MORE than I calculated. And the reason I
originally
did the calculations was to decide the purchase of an electric say 60
lbs or a 4
cycle outboard say 3 hp.

"Harry Krause" wrote in message
...
bowgus wrote:

Question ... when I did my 36 lb Min Kota calculation afew years
back,
the
answer I got was about 1/4 hp. Would you mind sharing your
calculation
(I've
since upgraded to a 55 lb thrust)? Thanks


"user" wrote in message
...
I have a 9'2" Sevylor XR-86 inflatable. It is powered by a 36 lbs
Minn Kota
Endura motor, about the same thrust as a 2.0 or 2.5 hp gas engine...
OK, it
doesn't plane. I'm not so sure it would plane with the maximum 3.5
hp
motor. I'm not so sure I'd want to do that anyhow.

Harry Krause wrote:
jake waldman wrote:


i'd like to get a 8'-9' inflatable with a 3hp engine. any
suggestions
would help.
do i go 2 stroke or 4.
it will be used for light duty.
thanks
jake


It's your choice. The small two cycle and four cycle outboards are
each
reliable, and don't burn a whole lot of fuel. With the four cycle,
you
don't have to mix oil in the gas can, and their exhausts smell
better. I
use a no-cycle outboard on my inflatable: an electric trolling
motor.




Wouldn't there be a way to compare pounds of thrust? My motorguide
trolling
motor produces-oh, I really don't remember-something like 65 pounds of
thrust,
maybe. How many pounds of thrust might a 3 hp gas outboard produce at
the
prop? A similar number? Larger?

The electric trolling motor is enough to push our rubber ducky around
the
harbor for a couple of hours, but if it craps out, no worry. We have
oars.

--
Email sent to is never read.

I too use a Minn Kota to push Near Cove around, and I too am confused
about
power.

Theory is pretty easy: Power can be measured in HP or Watts (746 Watts = 1
HP).
And wattage can easily be calculated: Max current for a 40-lb Minn Kota
(according to their website) is about 40 Amps. 40A at 12V is 480W, or 0.6
Hp.
That's "going in" so allowing for inefficiencies, say 1/2 Hp. BUT, even
the
30-lb'er I use pushes Near Cove like a 1 - 2 hp gas.

A couple of considerations: gas engines are a lot less efficient than
electric
motors. Also, there's a tendancy to run gas engines at less than full
throttle,
both for quietness and longevity, whereas there's no reason not to run an
electric "full throttle" except for how much it drains the battery.

Bottom line IMHO: an electric can push a dinghy just as well as a gas as
long as
you're not interested in planing, and it does it quieter and less smelly,
don't
need to store gas, etc.

Lloyd Sumpter
"Near Cove" Walker Bay 8 c/w Endura 30
"Tin Boat" Mirrocraft 12 c/w Maximizer 40